Figured I’d follow up on this post. I had to add an Aeotec Zstick to install firmware updates, because Smartthings does not support Zwave firmware updates. Everything you said above @JDRoberts is spot on, and boy Zwave networks DO NOT like having two controllers attached. It was temporary to just install firmware updates, but it caused all sorts of problems. It took me days to get my two switches that are near the edge of the range (in detached garage) stable and working again after attaching and removing this Zstick. I could not remove it from the network easily, as both Smartthings and the Zstick tried fighting for control. Putting the Zstick into exclusion mode is designed to exclude devices FROM the Zstick, not to exclude the Zstick from a different network. I had to reset the Zstick multiple times and really play around with the software with the classic app and IDE to get things working again. If there was no classic app, I have no idea how I would have fixed this. As I pointed out in this post - Get ready to make the switch! I am also realizing the limitations of Smartthings when it comes to Zwave control. It seems to me that the main purpose of Smartthings is to unify multiple different devices across different platforms. Up until the recent migration issues, it did that amazingly well, and hopefully when they work out the bugs, will continue to serve that purpose. However, for me, 90% of my devices are Zwave devices, which I installed 3-4 years ago probably when Zwave was “new and exciting”. I don’t have a lot of “cross platform” setups linked together through Smartthings like a lot of other people who I see posting on here. I still like Zwave and it has huge benefits over WIFI devices, but I am questioning its long term future, especially when Amazon’s newest Alexa went with Zigbee and no Zwave support. Most devices I have are “Zwave Plus”, but 3 are legacy Zwave - 2 Aeotec Micro Switches, and one GE/Jasco on/off. It annoys me that I have one toggle that is not Zwave Plus, because at the time I bought them from Amazon they were similar in price and I didn’t understand or realize the difference between the original and plus version. I really don’t want to rip these out every few years either - it is not good for the house’s wiring to constantly be flexing in and out of the wall. The wiring is not designed to do that, with “dumb” switches lasting more than 30+years, and I’ve already had wire break and as it gets shorter and shorter every time I replace a switch, I don’t want to have to rewire my whole house.
Anyway, as I pointed out in the other post, Zwave control seems to be absent in the new Smartthings app as well. I deleted a device and it just deleted it from the new app, but did not do an exclusion from the Zwave network, and also there was no option to force remove. If others do that, it will leave “ghost” devices on their Zwave network that will haunt it forever, and they will be left with no choice but to exclude every device, factory reset the hub, and start over, a daunting task for anyway, especially with a lot of devices and programmed automatons. Looking back on my purchase of Smartthings, I’m second guessing on whether it was the best choice for my setup.